Blowpipe



Dec. 23, 1941. w. J. JAcoBssioN ET Al. 2,267,104

BLOWPIPE Filed NOV. 4, 1939 I lNvENTORS WlLGoT J. JACOBSSON SAMUEL R. OLDHAM BY l 4, 'ATTO 'l Patented Dec. 23, 1941 BLOWPIPE wugoi J. Jacobsson, Plainfield, ana sam'u'ei n. Oldham, Newark, N. J., assignors to Oxweld 'Acetylene Company, a corporation of West,

Virginia Application'ivovember 4, 1939, serial No, 302,830` f s claims. (ci. 15a-27.4)` 1 This invention relates to cutting'and welding blowpipes generally, and has particular reference to improvements in deseaming, heat treating, cutting, and welding blowpipes in which a mixture of combustion-supporting gas'such as oxygen, and fuel gas such as acetylene, is used to maintainfa flame for heating material when the blowpipe is used for welding'and heat treating purposes, and in which aie't of oxygen is used with the preheating gases when the blowpipe is employed for cutting and deseaming purposes.

, A ilashback'isgenerally known as a recession of the flame inside the blowpipe,'where it continues to burn. A flashback is very undesirable, because, if allowed to continue, it will burn and ruin the blowpipe in a short time. If the rate at which the gas mixture leaves the blowpipe` tip always exceeds Ythe rate of propagation of the flame, flashbacks ordinarily will not occur. Accordingly, it is important to maintain at the blowpipe tip a rate of mixed gas travel which is greater than that 'of the flame propagation.

Since combustion-supporting gas is usually available at higher pressure than fuel gas, it is customary to use the flow of the combustion.- supporting gas to aspirate the fuel gas, to effect the mixing of the gases, and 'to' impart to the `gas mixture the necessary rate of travel at the blowpipe tip, When a blowpipe is used with a combustion-supporting gas at substantially constant pressure, a'change in fuel gas pressure may affect th'e composition of the gas mixture which the blowpipe delivers, as well' as the rate of propagation of j the mixed gases. The eiliciency and resistance of a low pressure blowpipe to flashback, therefore, are responsive to the fuel gas pressure'.

l.urtl i'ermore,v it is a well-,known fact that a lowpressure type blowpipe, so` called'lbecause thefuel gas is' supplied at a low pressure (less be used with fuel gasv atl either medium or lowy pressure with equal precision. Another object is the provision of a blowpipe jwhich may be I used with fuel gas at either medium or low pressure Without substantial alteration of its high resistance to flashback.k A further object is the provision of such a blowpipe in a form which does not require the removal and substitution of parts, or careful adjustment, when changing from fue1 gas at one pressure to that at another..l A still further object is to provide a cutting and welding blowpipehthat is simple `in construction and economical to manufacture,

of operation with either low or medium pressure acetylene with ahigh degree of flashback rethan 11b;/sq`.in. will operate satisfactorily with fuel gas at medium pressure (1 lb./sq. in o r greater), 'ifJ properly adjusted. j However, great care' isrduiredin'adjusting the fuel gas inlet valve when makingvjthe changeover, because of 4the sensitivityfo a :the blowpipe to fuel gas pressure. 'The 'bst'efliciency is obtained when a change in the amount of oxygen produces a corresponding change in the amount of acety- {lenedrawnv into the gas mixture. Such adjustnient takes valuable' time and is not always satisfactory. l

One object of the invention is, therefore, to 'provide ablowpipe having high emciency and flashback resistant characteristics, which .may

sistance in either case.

Other objects and' novel features of the invention will be apparent from the following description taken with the accompanying drawing, in which:

Fig. 1 is a fragmentary view in longitudinal cross section of a machine cutting blowpipe embodying features of the invention; Y

Fig. 2 is an enlarged' view in cross section taken on aline corresponding to line 2-2 of Fig. 1; land Fig. 3 is a fragmentary View in longitudinal cross section of a modification.

Considered from the points of view of construction and operating principles, all Oxy-acetylene blowpipes are of two general types, low pressure and medium pressure. The distinction refers to the acetylene pressure range required for operation. Acetylene supplied at pressures of less than 1 pound per square inch is designated as low pressure, and from 1 to 15' pounds persquare'inch as medium pressure. Low pressure blowpipes are capable'of using' acetylene from low pressure generators, mediumpressure generators, or cylinders. However, the' change from low pressure to medium pressure is generi ally accompanied by a loss of eiiiciency and a. loss of flashback resistance, as well as afloss of time. For medium pressure blowpipes, the acetylene pressure must be more than 1 pound per square inch. Medium blowpipes are capable of use with medium pressure generators or cylinders, but not with low pressure generators.

Low pressure blowpipes make use of what is known as the injector' principle. Oxygen at high velocity passes through a small opening in the injector nozzle, producing a suction eect which draws acetylene into the oxygen stream. One advantage of this type of construction is that small changes inthe amount of the oxygen iiowing will produce a corresponding change in the amount of acetylene aspirated, so that the proportions of the two gases remain substantially constant while the blowpipe is in operation.

In the present invention we secure the desirable advantages and features of a blowpipe of the low pressure type. while at the same time providing a blowpipe that is capable. through automatic o r quick manual changeover valve means, of utilizing either medium pressure acetylene or low prescombustion-supporting gas. ySuch valve means is preferably a throttling valve adapted tolower the acetylene pressureA around the injector sumciently to produce improved flashback resistance when the blowpipe is supplied with acetylene at medium pressure; said throttling valve being adapted also. when properly adjusted manually or automatically, to allow free substantially unrestricted flow of low pressure acetylene for low pressure operation with high resistance to nashbackl ThenoszleNisprovidedwithanaxialoxygen passage" terminating in' a restricted central outlet ll which acts to project a fine stream of high velocity heating oxygen into the gas mixing e or chamber Il in the casting l. The gas mixing' e Il is provided with a iiared outer portion Il which acts to further mix the gases, which are thereupon delivered to a series ofheatinggasesinthetip"l|.rrangecl` around the central cutting oxygen passage there- Mixing of the acetylene and oxygen gases takes place inthe passage Il, as pointed out above, the acetylene being delivered thereto through a fuel gas supply conduit, including a supply passage 2l having a valve chamber C in the valve block 1. and a'fuel gas delivery passage 2| in the casting l and the valve block 1, the latter including an elongated conduit 34 surrounding the passages of the nozzle N and the oxygen delivery tube II. 'I'he fuel gas supply passage 2l is provided with a .manually controlled valve 22 associated with the valve block 1. Thus. as oxygen passes through the small oriiice i1 of the injector nomle N, its

velocity is increased and a suction is produced that draws acetylene through the conical way 23 The throttling valve may be automatically or manually operated, an example of a manually operated throttling valve being shown in'Fgs. 1 and 2 of the drawing, and an automatically operated `acetylene throttling valve being shownin Flg.`3 of the drawing. AThe automaticallyoperated valve preferably is a small regulator built into the rear body 4of the blowpipe, whereas the manually operated valve is preferably a restrictive lorifice valve with one orifice of such' size as to give sumcient throttling over the entire range of possible pressures and consumptions to give improved iiashback resistance on mediuml pressure acetylene, and another oriiice large-enough to surrounding the nozzle N and into the mixing passage Il, through which the two gases then pass together and are delivered to the expanding passage Il, which insuresthorough mixing of the heating oxygen and acetylene so that the mixture issuing from the blowpipe tip T will burn Properly.

The Oxy-acetylene flame is produced at a series voi' openings in the blowpipe tip or nozzle which surround the larger central cutting oxygen orifice. as pointed out above. -As is well understood by those skilled in 'the'art, the function of the oxyacetylene heating llames in a cutting blowpipe such as shown inthe drawing is to preheat the metal that is-to be cut. -The use of a number of 'preheating flames, rather than a single one,

` makes itpossible to change the direction of the give excellent flashback resistance and sufficient` l acetylene flow for low ,pressure operation. a

Referring to the drawing, and to Figs. 1 and 2 'so in particular, the cutting blowpipe consists of a body portion B comprising an elongated tubular shell 4 within whichy is disposed a casting i, there being a ferrule 8 associated with the for..

. ward end of the body portion and a valve block 'I associated with the rearward end thereof. The valve block 1 has attached to it a nipple 8 to K which the cutting oxygen supply pipe or tube may be attached in any desired manner.

The valve block 1 isprovided with a cutting oxygen passage 9 having a.v manually controlled valve I0 associated therewith, the cutting oxygen [passage 9 being in series with a cutting oxygen passage Il in the casting 5, which delivers cutting oxygen to a central cutting oxygen passage in the blowpipe tip T, .which is secured to the ferrule 6 by a coupling nut i2 in a well-known manner.

The supply of heating oxygen is controlled -by for controlling the ow of fuel gas therethrough. The hollow cock 24 preferably is provided with` a stem 21, to the outer end of which is secured a handley 2l'in the form of a cup enclosing the cut as desired. In a blowpipe designed for weld- 1 ing or heat treating only, the oxygen and acetyiene for the heating name are mixed in the same manner-as in the machine cutting blowpipe described herein.

vAssociated with the acetylene delivery passage 2l in the'valveblock 1 is'a throttling valve M, preferably in the form of a hollowA cock 24 having a large opening 25 and a small opening 20 in its periphery..these openings being angularly spaced about degrees apart. The openings 2l and 28 are disposed in such angular relation that by turning thevalve M, one opening or the other may be presented alternatively in the e 2l cylindrical boss 29 on the valve block 1, and the packing gland nut 30, in spaced relation thereto. Gas leakage in the assembly'is prevented by a packing 3| which is urged into sealing associavtionwith the cock 24 by a compression spring I2 a manually operated valve llassociated with an A oxygen supply passage or conduit I4 in the .valve block 1, the supply of heating oxygen being delivered to an injector nozzle N through a heating oxygen delivery tube I5, which is connected at the rear end thereof with the vsupply passage i4 through a cross passage- (not shown).

acting through a washer 22.'

VIt will thus be seen that in the gas delivery passage 2| are provided a valve M having a large opening 25 and a small opening 2l in its periphery adapted to register alternatively with the gas delivery passage 2| to vary the rate of fuelgas flow through the delivery e, together with means 21 for turning said valve to cause either the large hole 2l or the small hole n wi11-umsbe seen `menos@ 'sinned in'" the..

26 therein to register with the gas delivery pas-f sage 2|, and means 3| sealing the valve cock 24 in thegas delivery passage 2| to prevent gas leakage past said turning means.V

Although the machine cutting blowpipe illustrated is of the low pressure type wherein a combustion-supporting gas is causedto aspirate and mix with a low pressure fuel-gas to maintain a fiame, the valve means M associated -with Y the fuel gas delivery passage 2| is lsuch that.

when the small orifice 26 is disposed therein. the iiow of fuel gas is so restricted by l'said small orifice 26 that fuel gas supplied to the blowpipe at medium pressure is reduced within the delivery passage 2I to a low pressure for aspiration by the combustion-supporting gas issuing from the injector nozzle N.

When it is desired to use the machine cutting blowpipe witha low pressure acetylene supply, the valve M is turned so that the large orifice 25 is presented in the fuel gas delivery passage 2|. Sufficient unrestricted acetylene flow is thus provided for low pressure operation. It will thus be seen by those skilled in the art that there is provided a blowpipe having the desirable operating characteristics and high flash-back resistance of a low pressure blowpipe, yet capable of precision use with fuel gas supplied at either medium pressures or low pressures.

Referring to Fig. 3 of the drawing, there is illustrated a blowpipe P of the low pressure type wherein a combustion-supporting gas is caused to aspirate and mix with a low pressure fuel gas to maintain a flame, substantially in the manner pointed out above in connection with the machine cutting blowpipe shown in Figs. 1 and 2. The blowpipe P comprises a Valve block 31 having an oxygen supply passage 38 and a separate acetylene supply passage 39. These passages are provided with control valves 40 and 4|, respectively, as well as with conventional connections 42 and 43 for the oxygen and fuel gas supply pipes or tubes, respectively.

The valve block 31 also has associated therewith an automatic fuel gas pressure responsive regulator valve A. The automatic pressure responsive va1ve;A preferably comprises a valve member 44 on a valve stem 45 which is secured by a head bolt art that the blowpipeshown in .Fig. 3 ofthe drawing operates in a manner-'substantially similar to that described previously in connection with thevmanually operated throttling. valve, but requiresno attention on the part of the operator. That is vto say,all` of the advantages and desirable characteristics inherent inA a blowpipe of the low pressure type are obtained bythe invention, whetherthe blowpipe isoperated on either low-pressure or medium pressurefuelgas; Blowpipes constructed according Ato the present invention vare very efcient and eifectivein operation, and highly resistant to flashback.

While the invention has been shown and described in detail, it is not to be limited to the exact form of construction described and illustrated, as it is obvious that various changes may be resorted to without departing from the spirit of the invention. Y r

We claim: f

1. In a blowpipe, the combination-with an vinjector for .injecting a combustion-supporting 6 to a diaphragm D in the centrai portion th reof, the outer periphery of the diaphragm D being secured within a cylindrical v boss 41 of the valve block 31 against an annular l internal shoulder by a cap screw 48 having a` vent 59. 'I'he position of the valve 44 in the valve chamber E relative to a valve seat 49 is controlled by a compression spring 50 disposed between the cap 48 and the diaphragm D, there being a locating and pressure distributing plate 5| for the spring 50 associated with the diaphragm D and secured in place by the bolt 46.

In operation, with the force of the spring 50 adjusted so that the valve 44 is properly spaced from the vvalve seat 49 for precision operation of the blowpipe with low pressure acetylene, when the blowpipe is connected to an acetylene source at medium pressure, the diaphragm D acts in response to the increase in the pressure of the fuel gas supply to close or restrict the effective opening of the automatic valve A so'that fuel gas is stepped down from medium pressure to low pressure on the discharge side of the regulator for aspiration by the combustion-supporting gas. The flow of 'fuel gas is through the connection 43, valve 4|, supply passage 39, valve A, and fuel gas delivery passage 52.

gas stream, passage means for delivering fuel gas adjacent to such injected combustion-supporting gas stream, said injector and said passage means being so designed that fuel gas at low pressure will be aspirated by combustionsupporting gas at relatively high pressure to provide a properly proportioned combustible gas mixture, separate gassupply conduits for said combustion-supporting gasand said fuel gas, respectively, and a control valve in each of said conduits; of valve means in said fuel-gas supply conduit adapted to maintain at low pressure the fuel gas delivered to said. passage means, said last-named valve means being operable either to permit the substantially unrestricted flow therethrough of fuel gas supplied thereto at low pressure, or to reduce to low pressure fuel'gas supplied thereto at medium pressure.

2. In a blowpipe of the low pressure type, wherein a combustion-supporting gas at high pressure is caused to aspirato and mix with a low pressure fuel gas to provide a combustible the fuel gas delivered to said mixing chamber,

said "last-named valve means being operable either `to permit the substantially unrestricted flow therethrough of fuel gas supplied thereto at low pressure, or to reduce to low pressure fuel gas supplied `thereto at medium pressure.

3. In a blowpipe, the combination with an injector for injecting a combustion-supporting gas stream, passage means for delivering fuel gas adjacent to such injected combustion-supporting gas stream for aspiration thereby, and separate supply conduits for supplying combustion-supporting gas and fuel gas, at least the fuel gas conduit having a Acontrol valve therein; of a manually controlled valve associated with said fuel gas supply conduit and independent of said combustion-supporting gas conduit, said last-named valve having a large opening for the substantially unrestricted iiow therethrough of low fuel gasand a small opening for medium pressure fuel gas, said last-named valve beingoperabletoregistersaidopeninssalternatively 'with said fuel. gas supply conduit, said smallopeningbeingadaptedtoreducetolow pressure fuel gas supplied thereto at medium pressure for aspiration by said high pressure combustion-supporting gas.

4. In a hlowpipe, the combination with an in jector for injecting a combustion-supporting gas stream, passage means for delivering fuel gas adjacent to such injectedcombustion-supporting gas stream, said injector and said passage means `being so designed that fuel gas at low pressure will be aspirated by combustion-supporting gas at relatively high pressure to provide. a properly proportioned combustible gas mixture, and separate`.gas supply conduits for said combustion supporting gas and said fuel gas. respectively, atleast the fuel gas supply conduit having a control valve therein; ci' a hollow cock valve in :,aemos said small openopening to register with the for maintaining said fuel gas supply conduit: and means sealing said cock valve in said fuel gaa-supply conduit to prevent leakage past said turning means.

5. In a blowpipe. the combination with an injector for injecting a combustion-simporting gas stream, passage means for delivering fuel gas adjacent to such injected combustion-supporting gas stream for aspiration thereby. and separate supply conduits for the combustion-supporting gas and the fuel gas: of an automatic fuel gas pressure responsive pressure regulating valve associated with said fuel gas supply conduit and independent oi said combustion-supporting gas conduit, said pressure regulating valve being adjusted to maintain a low pressure on the discharge side thereof, thereby so controlling the flow of fuel gas that fuel gas supplied at medium pressure is reduced within said pressure regulating valve to low pressure and delivered to said passage means for aspiration by the high pressure combustion-supporting 838.

WILGOT J. JACOBSSON. SAMUEL R. OLDHAM. 

